Unveiling the nature of the highly absorbed X-ray source SAX J1748.2-2808 with XMM-Newton

¹ Istituto di Astrofisica Spaziale e Fisica Cosmica - Sezione di Milano – INAF-IASF, 20133 Milano, Italy e-mail: sidoli@iasf-milano.inaf.it
² Research and Scientific Support Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
³ Science Payload and Advanced Concepts Office, ESA, ESTEC, Postbus 299, 2200 AG, Noordwijk, The Netherlands

Received: 12 April 2006
Accepted: 6 June 2006

Abstract

We report on the results of an EPIC XMM-Newton observation of the faint source SAX J1748.2-2808 and the surrounding field. This source was discovered during the BeppoSAX Galactic center survey performed in 1997–1998. A spatial analysis resulted in the detection of 31 sources within the EPIC field of view. SAX J1748.2-2808 is clearly resolved into 2 sources in EPIC images with the brighter contributing almost 80% of the 2–10 keV flux. Spectral fits to this main source are consistent with an absorbed power-law with a photon index of and absorption equivalent to  cm^-2 together with an iron line at  keV with an equivalent width of  eV. The significantly better statistics of the XMM-Newton observation, compared with BeppoSAX, allows to exclude a thermal nature for the X-ray emission. A comparison with other observations of SAXJ1748.2-2808 does not reveal any evidence for spectral or intensity long-term variability. Based on these properties we propose that the source is a low-luminosity high-mass X-ray binary located in the Galactic center region.